JPH02211799A - Acoustic reproducing device - Google Patents

Abstract

PURPOSE:To obtain well balanced sound quality as a whole by correcting peaks and dips caused considerably in side location sound through more or less sacrifice of center location sound. CONSTITUTION:The acoustic reproducing device consists of interconnecting attenuators (variable resistors) 6-9, differential amplifier circuits 1-3, delay circuits 4, 5, low pass filters 11, 13, a band pass filter 12, adder circuits 14-19, and an inverter 21 or the like. The attenuators 6, 7 and the adder circuits 14, 15 constitute a crosstalk addition means, signals of other channels are attenuated and synthesized and then fed to the delay circuits 4, 5 to limit the spread of sound image through cancelling crosstalk. Thus, a natural sense of sound field is obtained, in which sound quality deterioration is less, sound image location is not excessively spread and sound quality is well balanced as a whole.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sound reproduction device, and particularly in stereo reproduction using two speakers, performs binaural crosstalk cancellation and eliminates the level difference 1 included in the original signal. The present invention relates to an improvement in a sound reproduction device that can accurately reproduce time difference information.

[Conventional technology]

In stereo systems having two independent speaker systems and audio circuits, such as 2ch (channel) stereo equipment, some systems have conventionally been equipped with a function to cancel interaural crosstalk during 2ch speaker playback. For example, as a typical example of utilizing the difference between both signals, a circuit configuration as shown in FIG. 3 has been proposed up to now. 4 is a delay circuit, 16.17 is an adder circuit, and 21 is an inverter. With this configuration, the output signals L7 . R7 is LT=L+ (LR) At...
・・・・・・(1) RT=R+ (RL)a t
・・・・・・・・・・・・・・・(2), furthermore,
The method of determining the delay time Δt in the delay circuit 4 also includes a phase shifter (fPhase 5hif-ter) method,
Various methods have been proposed, including a BBD method, a digital method, and a speaker method.

In addition to the configuration in which the difference signal of both R channels is used in the differential amplifier 3, as shown in FIG. 4, a delay circuit 4.
5 delays both signals by that i, 1, and inverter 2
There is also a configuration in which, after inversion at step 1.22, adder circuits 16 and 17 add each other to other channels and output the results.

The output signals LT and RT of each R ah are L T = L RA t ・・・・・・・・・
・・・・・・・・・・・・・・・ (3) RT=R−L
Ot ・・・・・・・・・・・・・・・・・・・・・
(4), which is a method developed by the applicant company that is widely contradictory to pyphonic technology.

[Problem to be solved by the invention]

Stereo signals can be roughly divided into centrally located sounds (L.

There are two signals: R in-phase component) and lateral localization sound (L, R uncorrelated components). Furthermore, when a signal is delayed for a certain period of time, the phase naturally rotates linearly with frequency, and in-phase and anti-phase components appear periodically with respect to the original signal. When this signal is added and subtracted from the original signal, the peak is obtained.

A dip appears and the sound quality changes.

Furthermore, in the conventional differential circuit shown in FIG. 3, the output signal LT=L±(L−R)At or RT=R+
(R-L)at contains a delay signal (=
center localized sound) is not output, and the result of addition is
However, for the uncorrelated component (L-R) or the side localized sound that is not removed by (R-L), it becomes L+LAt and R+RAt, respectively.
As shown in Figure 5, in normal stereo playback in which peaks and dips occur at a period of 1/2 At, the delay time a
Since t is set to 10 (approximately 1 to 200 μs, the first
The dip (2a t ) −' has a frequency of 2.5 ~ 5
This occurs in the treble part of H2, and as a result, the sound reproduced from the speaker becomes a muffled sound with poor auditory clarity. In other words, although there is no change in the centrally located sound,
A change will occur in the lateral localization sound.

Furthermore, in the conventional circuit using the original signal delay method shown in FIG. However, since the centrally located sound is a correlated component, it will change. In other words, as shown in Fig. 6, the dip and peak occur at a period of 1/2Δt, and the first
The peak (2t)-1 is at frequency 2.5 ~ 5 at H2
Since the low frequency components of normal stereo recordings are recorded in approximately the same phase, the center-localized sound played from the speakers will be audibly very thin with very little low frequency components. This means that the relationship between the side localized sound and the center localized sound is reversed compared to the circuit shown in Figure 3 above, but in any case, with conventional devices, the sound quality of either localized sound is different. The disadvantage was that it deteriorated.

[Means to solve the problem]

The sound reproduction device of the present invention has the following features: 1. The first channel delays the input audio signal of the second channel by a predetermined amount. a second delay circuit; a first differential amplifier that outputs a signal corresponding to the difference between the input audio signal of the first channel and the signal output of the first delay circuit; a second differential amplifier that outputs a signal according to the difference in signal outputs of the delay circuits; and a third differential amplifier that outputs a signal according to the difference in signal outputs of the first and second delay circuits. , 1st. The first one reduces the high frequency components of the signal output of the second differential amplifier. a second low-pass filter, a band-wave filter that reduces frequencies other than mid-range components of the signal output of the third differential amplifier; 2nd low range P
The first step is to adjust the level of the output signal of the wave generator. a second attenuator; a first addition circuit that adds the signal output of the bandpass filter and the input audio signal of the first channel; and a signal obtained by inverting the signal output of the bandpass filter and the input audio signal of the second channel. a second adder circuit that adds the first . The signal output of the second adder circuit and the signal output of the first adder circuit. The third attenuator adds the signal output of the second attenuator and outputs the resultant signal. The above-mentioned drawbacks are improved by including a fourth addition circuit.

〔Example〕

An embodiment of the sound reproduction device of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of a device according to an embodiment of the present invention. In this figure, the same components as those of the conventional device shown in FIGS. 3 and 4 are given the same numbers, and the details thereof are Explanation will be omitted. As is clear from FIG. 1, the sound reproduction device of the present invention includes attenuators (variable resistors) 6 to 9, differential amplifiers 1 to 3, and delay ports fI? I4
, 5, low-pass filters 11 and 13, band P wave filter 12, adder circuits 14 to 19, and inverter 21, etc., and these are connected as shown in FIG. Note that the attenuator 6.7 and the adder circuit 14.15 constitute crosstalk adding means, and in this way, the signals of the two channels are attenuated and combined, and then supplied to the delay circuit 4.5. This is to limit the spread of the sound image depending on the music source due to crosstalk cancellation, but it does not necessarily have to be present. In addition, addition circuit 1
7 and the inverter 21, one subtraction circuit may be used.

Hereinafter, the functions and operations of the device of the present invention will be explained with reference to the frequency characteristic diagram shown in FIG. The input audio signal of the LCh is attenuated by a predetermined amount by an attenuator 6, and then sent to an adder circuit 1.
The signal is added to the Rch input signal at step 5, delayed by a predetermined amount at delay circuit 5, and then supplied to the inverting input terminals of differential amplifiers 1 and 2.

Similarly, the Rch input signal is attenuated by a predetermined amount in the attenuator 7, added to the LCh input signal in the adder circuit 14, and delayed by a predetermined iM in the delay circuit 4, and then inverted by the differential amplifier 3. It is supplied to the input terminal and the non-inverting input terminal of the differential amplifier 2. Since the Lch and Rch input audio signals are directly supplied to the non-inverting input terminals of the differential amplifiers 3 and 1, respectively, the output terminals of the differential amplifiers 3 to 1 output L-LAt (see Figure 2). ), (LR) At, R-
A signal Rat is output. The outputs of the differential amplifiers 3 and 1 have their high-frequency components reduced (removed) by low-pass filters 11.13, and then are appropriately filtered by attenuators 8.9, which adjust the levels for characteristic correction. The signal is attenuated (the attenuation rate is α) and supplied to the adder circuit 18 and one filter. Note that the low-pass filters 11 and 13 perform high-frequency attenuation as shown by the broken line in FIG. The main purpose is to reduce the peak value of the high frequency range (reduce bounce).

On the other hand, the output of the differential amplifier 2 is supplied to the bandpass filter 12, where the low frequency range of the crosstalk canceling signal is removed (to reduce the feeling of out-of-phase in the low frequency range), and to stabilize the localization. The high frequency is removed by the adder circuit 16. and is supplied to the adder circuit 17 via the inverter 21. The input audio signals of t, ch, and Rch are directly supplied to the adder circuits 16 and 17, and after adding the output signals of the bandpass filter 12 and the inverter 21, respectively, the output signals of the attenuators 8 and 9 are added. The signals are added in adder circuits 18 and 19 and output. With the above configuration (assuming that there is no attenuator 6.7), the output signal LT (
(See Figure 2), RT is LT = L + (L R) Δ, respectively.
t + αL (1-at) ・・・・・・・・・・・・・・・
・(5) RT=R+ (RL),! kt + αR (1-At) ・・・・・・・・・・・・・・・
・(6) As a result, the intense peaks and dips (see Figure 2 (^)) of the side localized sound (L, R uncorrelated components) are converted to the center localized sound (L, R in-phase components: Figure 2) (See (B))
The sound quality (frequency characteristics) is well-balanced as a whole by correcting some wrinkles.

That is, a natural sound field feeling can be obtained with less deterioration in sound quality than with conventional devices, and with no excessive spread of sound image localization.

Note that the sound reproduction device of the present invention aims to eliminate the presence of speakers in principle and accurately reproduce the "localization information" based on the level difference and time difference included in the original signal, so the sound reproduction device is Of course, if the desired music X-S is recorded including a large amount of such information (for example, by well-known dummy head recording, OSS recording, 0RTF recording, etc.), the effects of the apparatus of the present invention will be even greater.

〔effect〕

Since the sound reproduction device of the present invention is configured as described above, there is less deterioration in sound quality compared to conventional devices, the sound image localization does not spread too much, and a natural sound field feeling with a well-balanced sound quality as a whole can be obtained. It has the feature of being able to

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a sound reproduction device according to an embodiment of the present invention, and FIGS. 2 (A) and (B) are frequency characteristics for explaining the improvement operation of side-localized sound and center-localized sound, respectively, in the device of the present invention. Figures 3 and 4 are block diagrams of conventional devices;
5 and 6 are frequency characteristic diagrams of each localized sound in the conventional apparatus shown in FIGS. 3 and 4, respectively, and FIG. 7 is a frequency characteristic diagram for explaining the function of the low-frequency wave generator constituting the apparatus of the present invention. It is. 1-3... Differential amplifier, 4, 5... Delay circuit, 6-
9...Adutenator (variable resistor), 11.13...
・Low-pass filter, 12...Band filter, 14-19...
-Addition circuit, 21...inverter. Patent applicant: Victor Japan Co., Ltd. Representative: Kunio Umiki 71 Figure 2 Figure W6 Figure zZ

Claims (1)

[Claims] In a sound reproduction device that performs two-channel stereo reproduction by canceling crosstalk between both ears, the first
, first and second delay circuits that respectively delay the input audio signal of the second channel by a predetermined amount, and output a signal according to the difference between the input audio signal of the first channel and the signal output of the first delay circuit. a first differential amplifier; a second differential amplifier that outputs a signal according to the difference between the input audio signal of the second channel and the signal output of the second delay circuit; and the first and second delays. a third differential amplifier that outputs a signal according to the difference in signal output of the circuit; and first and second low frequency components that reduce high frequency components of the signal outputs of the first and second differential amplifiers, respectively. A filter and
a bandpass filter that reduces frequencies other than midrange components of the signal output from the third differential amplifier; and first and second bandpass filters that adjust the levels of the output signals of the first and second low-pass filters. an attenuator, a first addition circuit that adds the signal output of the bandpass filter and the input audio signal of the first channel, a signal obtained by inverting the signal output of the bandpass filter, and the input audio signal of the second channel. and third and fourth adder circuits that add and output the signal outputs of the first and second adder circuits and the signal outputs of the first and second attenuators, respectively. A sound reproduction device comprising: